1. Field of the Invention
The present invention relates to a liquid delivering device such as an inkjet head which effects recording on a recording medium by means of ejecting ink on the same.
2. Description of the Related Art
An inkjet head, which has hitherto been known, has a piezoelectric actuator which deforms a piezoelectric layer by subjecting the piezoelectric layer to an electric field, and ink is ejected by application of pressure, by means of the piezoelectric actuator, to the ink stored in a pressure chamber (see JP-A-11-334087 (see FIG. 3)). The inkjet head piezoelectric actuator disclosed in JP-A-11-334087 is a unimolf-type piezoelectric actuator including a diaphragm which also functions as a lower electrode (a common electrode); a piezoelectric layer formed from lead zirconate titanate (PZT) or the like made on the surface of the diaphragm; and a plurality of upper electrodes (individual electrodes) formed on the surface of the piezoelectric layer in correspondence with a plurality of pressure chambers. In this piezoelectric actuator, when a drive voltage is applied selectively to the plurality of upper electrodes, an electric field acts on the area of the piezoelectric layer sandwiched between the electrodes (a drive section) in a thicknesswise direction thereof, whereupon the drive section extends and contracts. In association with extension and contraction of the drive section, the piezoelectric layer and the diaphragm, which are located in the area opposing the pressure chamber, are deformed to thus apply pressure to the ink in the pressure chamber. The piezoelectric layer is formed continuously over the surface of the diaphragm across the plurality of pressure chambers by means of the sol-gel method, the reactive sputtering technique, the vacuum deposition method, or the like, whereby the piezoelectric layer corresponding to the plurality of pressure chambers is formed by one operation. The upper electrodes that cause the electric field to act on the piezoelectric layer are formed smaller than the pressure chamber, and the drive section assumes a size smaller than the pressure chamber. When the drive section extends or contracts upon exposure to the electric field, areas surrounding the drive section are also deformed in association with extension and contraction of the drive section. As a result, the piezoelectric layer and the diaphragm of the entire area opposing the pressure chamber are deformed.